Today, communications service providers have legacy networks deployed that handle voice calls from millions of subscribers and generate the majority of the service providers' revenue. The legacy networks are typically circuit switched telephone networks either for wireline or wireless voice service. The service providers also have legacy applications deployed that connect to their legacy networks and provide revenue generating services to the subscribers. These applications are usually deployed using Intelligent Network (IN) architecture, employing Service Control Point (SCP) systems. Often the SCP relies on Intelligent Peripherals with Service Resource Function (SRF) capability to play tones and announcements, collect dialed digits, provide speech recognition, or convert text to speech when it is required for the application. Examples of legacy voice applications are Freephone, Prepaid Card, Calling Card, Premium Rate, Televoting and many others.
The service providers are also deploying next generation networks that are based on packet switching technology using Internet Protocol (IP) communications. Next generation networks based on IP communications provide the service providers with new, enhanced, multimedia applications that promise to drive new revenue streams. Next generation network architectures such as the IP Multimedia Subsystem (IMS) defined by the 3rd Generation Partnership Project (3GPP) standards body or broadband next generation network (NGN) architectures utilizing softswitch and media gateway standards, utilize Voice-over-IP (VoIP) technology for basic voice service. The service providers are also deploying next generation applications that connect to their next generation networks. These applications are usually deployed in Application Servers (AS), Service Delivery Platforms (SDP) or similar server clustering technologies. Often the AS relies on Media Servers (MS) to play tones and announcements, collect dialed digits, provide speech recognition, or convert text to speech (much like the Intelligent Peripheral for SCPs) when it is required for the application. Examples of next generation voice applications are Unified Messaging, Video Calling, Voice Enabled Web Applications, and many others.
The quandary that the service providers face is how to transition their revenue generating legacy networks to next generation networks. The next generation networks have limited revenue streams today, but promise even greater revenue in the future. The service provider has to build the next generation network as an overlay network alongside the legacy network and operate both networks in parallel. The reason is that it is not realistic for the service provider to build the next generation network, perform a flash cutover of all subscribers to the new network and then decommission the legacy network. As subscribers are migrated to the next generation network they still need access to the legacy voice services. The service provider could replicate all of the legacy voice services using next generation applications, but this approach would be costly and requires that all legacy applications be available on day one on the next generation network. Likewise, deployed next generation applications may be useful for subscribers still using the legacy network.
Therefore, a need exists for communications service providers to reuse legacy applications on next generation networks and use next generation applications on legacy networks. This allows the service providers to easily move subscribers to the next generation network, still offer the same familiar legacy voice applications, and control capital equipment costs for new or ported applications on the next generation network. Furthermore there exists a need to enhance connectivity of applications to networks more generally.